1. Field of the Invention
The present invention relates to a liquid crystal device and to electronic equipment, and in particular, relates to a liquid crystal device in which only slight deterioration of an orientation film over time is exhibited, contrast slightly decreases even in the case of longterm use, and display quality is improved by increasing the axial orientation in a horizontal direction, and relates to electronic equipment equipped with the liquid crystal device described above.
2. Description of Related Art
A liquid crystal device for use as a light modulating device to be mounted on a projection type display device such as a liquid crystal projector, or a direct viewing type display device to be mounted on a mobile phone, or the like, mainly comprises a pair of substrates which are arranged to face each other by interposing a liquid layer therebetween, and are equipped with electrodes for applying a voltage to the liquid crystal layer described above. On the uppermost surface, directed to the liquid crystal layer, of each of the pair of substrates for forming the liquid crystal device, an orientation film is formed for controlling alignment of liquid crystal molecules when no voltage is applied. In addition, a structure is provided, in which by optically identifying the alignments of liquid crystal molecules when no voltage is applied and when voltage is applied, respectively, display can be performed.
As orientation films, in general, those wherein the surface of a polymer film such as a polyimide film is subjected to a rubbing treatment are suitably employed. By employing the orientation film having the structure described above, the orientation condition of the liquid crystal molecules when no voltage is applied can be regulated by molecular interaction between the orientation polymers and liquid crystal molecules.
In these liquid crystal devices, a structure to improve reliability of the display, which is a passivation film (coating film) composed of a magnesium compound, is formed on a glass substrate, and an electrode formed from ITO (indium tin oxide) is provided on the passivation film, has been proposed (see, for example, Japanese Unexamined Patent Application, First Publication No. Sho 61-128225, and the like).
On the other hand, in order to orient a liquid crystal, as a structure for controlling a form of an orientation film per se, a product having a structure wherein an orientation controlling layer having a sawtoothed cross-sectional form and being composed of a film of a polymer such as an optically curable resin or a photosensitive resin is provided on a substrate has been proposed (see Japanese Unexamined Patent Application, First Publication No. Hei 1-238619; Japanese Unexamined Patent Application, First Publication No. Hei 9-152612; Japanese Unexamined Patent Application, First Publication No. 2000-155318; and the like).
However, when a liquid crystal device employing a polymer film such as a polyimide film as an orientation film is applied to, for example, a liquid crystal light valve for use in a liquid crystal projector, after longterm use, the polymer film, such as a polyimide film, is deteriorated by the light or heat. As a result, problems arise in that the quality of the display is degraded and reliability is reduced.
In addition, in the liquid crystal light valve described above, in the case of employing ITO as a transparent electrode for driving a liquid crystal at the lower side of the orientation film, if indium (In) or tin (Sn) deposited from the ITO electrode dissolves into the liquid crystal layer, the electric properties of the liquid crystal light valve are altered. As a result, problems arise in that the quality of the display is degraded and reliability is reduced.
In addition, in the structure in which a passivation film is formed on a glass substrate, although effects of preventing dispersion of metal elements such as sodium contained in the glass substrate can be obtained, dissolution of In or Sn deposited from the ITO electrode into the liquid crystal layer cannot be prevented.
Furthermore, when the liquid crystal device having a sawtoothed orientation-controlling layer formed from a polymer film such as an optically curable resin film or a photosensitive resin film, is applied to, for example, a liquid crystal light valve for use in a liquid crystal projector, after longterm use, the polymer film such as an optically curable resin film or a photosensitive resin film is deteriorated due to light or heat. As a result, problems arise in that quality of the display is degraded and reliability is reduced.